Chocolate Roulade

1. FOR THE FILLING: Bring cream to simmer in small saucepan over high heat. Off heat, stir in confectioners’ sugar and espresso and let cool slightly. Gently whisk cooled cream mixture into softened mascarpone until combined. Cover with plastic wrap and refrigerate until ready to use.
2. FOR THE CAKE: Adjust oven rack to lower-middle position and heat oven to 350 degrees. Grease 18 by 13-inch rimmed baking sheet, line with parchment paper, grease parchment, then flour pan. Whisk flour, cocoa, baking powder, and salt together in medium bowl; set aside.
3. Using stand mixer fitted with whisk, whip eggs on medium-high speed and gradually add sugar, about 1 minute. Continue to whip mixture until very thick and voluminous, 4 to 8 minutes. Whip in vanilla. Sift flour mixture over egg mixture and fold with rubber spatula until just incorporated.
4. Scrape batter into prepared baking sheet and spread out to even layer. Bake cake until it feels firm and springs back when touched, 12 to 17 minutes, rotating baking sheet halfway through baking. Lay clean kitchen towel on work surface.
5. Immediately run knife around edge of cake, then flip hot cake out onto towel. Peel off and discard parchment. Starting from 1 long end of cake, roll cake and towel snugly into log and let cool, seam side down, for 15 minutes.
6. Using stand mixer fitted with paddle, beat filling on medium-high speed until stiff, 10 to 30 seconds. Gently unroll cake. Spread filling over cake, leaving 1⁄2-inch border at edges. Reroll cake gently but snugly around filling, leaving towel behind as you roll. Trim ends of cake on diagonal.
7. Line edges of cake platter with 4 strips of parchment paper to keep platter clean. Place cake roll on prepared platter. Frost cake evenly with frosting and if desired, drag fork through frosting before it sets to make wood-grain striations. Carefully pull out pieces of parchment from beneath cake before serving. (Cake can be covered lightly with plastic wrap and refrigerated for up to 1 day. Let sit at room temperature for 30 minutes before serving.)

ASSEMBLING CHOCOLATE ROULADE
1. Starting with long side, gently roll cake—towel and all—into jelly roll shape. Cool for 15 minutes.
2. Spread chilled filling evenly over unrolled cake, almost to edges, and reroll cake gently but snugly around filling, peeling off towel as you roll.
3. Trim both uneven ends of roulade on diagonal.
4. Spread frosting over roulade. If desired, drag fork through icing before it sets to make wood-grain striations.